It has been years since I did it. Eaten a burger from McDonald’s, that is. But news that one of the four McDonald’s restaurants in the Olympic park is — temporarily anyway — the biggest on the planet made me think I should try again. I mean, the building is probably visible from space.

The first McDonald’s in London, which opened in 1974 in Powis Street, Woolwich, is still trading. Back then a burger cost 18p and a Big Mac was called a Big Boy (with similarly dazzling naïvety or absence of irony, McDonald’s earlier this year launched a promotional game with cash and other prizes called Monopoly).

The cheeseburger with which I chose to sacrifice my Mac virginity — you heal over after a few years if you haven’t had one — cost 99p. It is not much money for meat, cheese (or some sort of dairyish substance), a smear of ketchup and a bun, but it was a deeply demoralising object in both appearance and taste.

The Gastronaut, aka food writer Stefan Gates, recently revived the notion of the bum sandwich to which Fanny Cradock was partial. The idea is that you sit on a well-wrapped sandwich — or it could be a currant bun — and after about an hour, a constant body temperature of 37C and your body weight turn you into a human Breville, which flattens and “cooks” the assembly. The McDonald’s cheeseburger was indeed a bum sandwich in every sense of that notion: the tasteless grey disc of beef thin and flat, the cheese earwaxy, and the bread collapsed pap. Apart from the price — but you could make an omelette with two medium free-range eggs from Asda for about 33p — there is nothing whatsoever positive to say about it.

Interestingly, two of the “food” sponsors, McDonald’s — which is counting on up to 1,200 customers an hour and £3 million sales at the Olympic Park — and Cadbury’s, contribute a relatively tiny amount of funding given their conspicuousness and disproportionate ability to dominate. One example is McDonald’s edict that no other catering outlet in the park is allowed to sell chips unless it is with fried fish — fish and chips being apparently sacrosanct. The Children’s Food Campaign, which has issued a report entitled The Obesity Games, claims that together these two companies account for only a fraction of the IOC income. So next time, why not drop them and at a stroke — or less likelihood of a stroke — improve the image of the Games?

As far as I know, no one has put forward the argument that, of all people, athletes are probably best suited to dealing with McDonald’s and Cadbury’s — the last perhaps in the beguiling form of a McSlurry, sorry, Flurry — since they expend upwards of 3,000 calories a day in their physical efforts. However, when you read about athletes’ diets, carb-loading usually takes the form of porridge, grains, pasta and bananas. Sir Roger Bannister, who in 1954 ran a mile in less than four minutes, relied on tinned pilchards for his prowess.

Go-faster foods are a branch of nutritional science that has yet to recommend burgers, pizza or fried chicken — although Usain Bolt claims to have adhered to a diet of chicken nuggets at the 2008 Beijing Olympics — but fast food offered in London in the past year or so has fortuitously taken a phenomenal leap onwards and upwards.

Eating on the hoof is nothing new. In medieval times — as Danny Boyle might have depicted and then fast-forwarded to the queues outside MEATliquor, Pitt Cue or Rita’s Bar & Dining — the labouring classes bought their pasties and hot pies from street stalls or shops. They did not have the wherewithal to cook at home. Now that so many have the stove but not the inclination and do not want to be left out of the merriment of eating out, there are vans, trucks, stalls and street markets devoted to cooked food and young entrepreneurs keen to do things well and remove the stigma of unhealthiness and exploitation from fast food.

The trajectory goes something like this. Someone passionate about, say, pizza made the way it is in its home town of Naples will go to great lengths to get the right wood-fired oven with an ability to reach the necessary high heat, the correct flour, the best tomatoes available and so forth. Punters realise that a slice of this life is completely different from the offering of a chain restaurant. Enough money comes in so that the pizza obsessive can expand — slowly. When this is repeated for BBQ pork, udon noodles, burgers, tacos, bahn mi, sliders, Southern fried chicken, Indian thalis, kimchi, hot dogs, bhel puri, paella, churros and more, a culture of greater expectations of affordable, diverting food and its rightful place in enjoyment builds up.

Petra Barran, founder of www.eat.st, the website with the information for the collective of street traders that gathers three times a week at King’s Boulevard behind King’s Cross station, and currently (until August 12) every day in Exhibition Road SW7, campaigns for the normalisation of eating well, an experience accessed by all. “We lead such choreographed lives,” she says. “Street food is about ruffling up the unexpected … shaking off the auto-pilot.” It represents and extols the antithesis of what mass-market food manufacturers — and also event organisers complete with armies of security guards — want to impose and profit from. Street food is liberating and by definition adheres to the virtues of local, sustainable and impatient of waste. When it runs out, it runs out with maybe just a crumpled paper napkin left to show anything was ever there.

Individual traders are organising in places such as Maltby Street in Bermondsey, Broadway Market and Netil Market in London Fields, Portobello and Golborne Road Markets, Southbank, Whitecross Street and Leather Lane in EC1, Lower Marsh in Waterloo, Greenwich Market and more — all over the city. Now is the time to vote with our feet against the giants of fast food and their life-denying stamped-out discs of mere subsistence. See you for feijoada in Rio.